The present invention relates to a tumor marker for pancreatic cancer and a method for determining (diagnosing/testing) pancreatic cancer.
Pancreatic cancer is a typical intractable cancer, and the prime reason for the obstinacy is difficulty in early diagnosis.
Currently, as tumor markers (diagnostic markers) for pancreatic cancer, CEA, CA19-9, CA-50, elastase 1, Span-1, DUPAN-2 and the like have been developed and used in clinical diagnosis. However, since there remains some problems that these tumor markers are detected as positive not only in pancreatic cancer, but also in benign hepatic disorders such as chronic hepatitis and hepatic cirrhosis as well as in chronic pancreatitis, and in tumors other than pancreatic cancer (e.g. stomach cancer, colon cancer), or detected as negative in a particular pancreatic cancer, these markers are not satisfiable with respect to the specificity and accuracy in detecting and diagnosing pancreatic cancer.
On the other hand, haptoglobin is a glycoprotein having specific affinity for hemoglobin. The human haptoglobin is a tetramer composed of 2 subunits (α- and β-) with molecular weight of about 90 KD, and classified into 3 types including haptoglobin 1-1 (Hp1-1), haptoglobin 2-1 (Hp2-1) and haptoglobin 2-2 (Hp2-2).
In recent years, the relationship between fucosylated haptoglobin and various types of cancers has been studied, and it has been pointed out that the fucosylated haptoglobin may be useful for the detection of pancreatic cancer (non-patent reference 1: Okuyama N, et al., Int J Cancer. Jun. 1, 2006; 118(11):2803-8).